This invention relates generally to apparatus for monitoring air pressure, and more particularly to an air pressure monitor adapted for use with a seed planting machine of the type utilizing a rotating drum with pressurized air applied thereto for the planting of seeds.
In many types of machines, apparatus and systems, it is necessary or desirable to monitor an air pressure for providing an indication thereof to an operator of the machine, apparatus or system. While the apparatus according to the present invention may be used for pressure measurement or monitoring in a wide range of applications, the disclosure will be facilitated by addressing the problem of monitoring air pressure in a seed planting machine.
Automatic seed planting apparatus has been developed to facilitate the planting of large fields of crops by a farmer with a minimum of time and manpower. Such seed planting apparatus may be equipped with a plurality of seed dispensing nozzles so that a plurality of rows of seed can be planted in a single pass over a particular area of field. For example, four, six, eight or more rows can be planted during a single planting operation. One type of seed planting apparatus contemplated for use with the present invention is one wherein a large hopper or hoppers containing seed to be planted is positioned for delivering seed to a rotating drum. To facilitate delivery of the seed from the hopper to the drum and from the drum to the ground, a power driven blower supplies air under pressure to the hopper and drum through a suitably connected air duct. The hopper and drum pressures are maintained substantially equalized. The drum includes a plurality of apertures or pockets formed in rows about the circumference of the interior circular wall of the drum, the number of apertures or pockets per row corresponding to the number of rows planted simultaneously by the planter. Near the top of the revolving drum, on the exterior surface thereof, a seed release wheel contacts each pocket and releases the seed held therein. As the seeds are released from the pockets they are caught by the air flow produced by the blower and carried through a discharge manifold positioned in registry with the pockets and release wheels, to respective delivery tubes where the seeds are dispensed in their appropriate rows.
In such a seed planting apparatus, the pressure in the drum must be controlled to obtain a suitable amount of pressure for holding the seeds in the pockets and dispensing the seeds through the manifold. For example, in order to properly dispense light seeds such as beets, three to four ounces of pressure should be maintained in the drum, whereas to dispense relatively heavy seeds such as corn, ten to twelve ounces of pressure should be maintained. Heretofore, a mechanical pressure gauge was generally mounted on the planter, for example, on a hopper thereof to monitor the air pressure of the hopper and drum. A suitable regulating mechanism such as a manually actuatable valve is provided, accessible to an operator for adjusting the power driven blower to supply the desired amount of air pressure for the particular seeds being planted. Thus, it is necessary for a farmer utilizing such a planting apparatus to periodically look behind the tractor to visually inspect the pressure gauge on the planter to insure that the proper air pressure is being maintained.